The IUE spectrum of the early-type eclipsing binary mu1 Scorpii.

Abstract

The ultraviolet spectrum of the system Mu1 Scorpii at two phases of the orbital cycle is described. The presence of resonance lines of Si IV and C IV suggests that there are nonthermal sources in the system. The spectrum displays absorption lines that appear to follow the orbital motion of either component. The spectrum also displays sharp absorption features of which some, at least, must arise in the interstellar medium and part of which, perhaps, in the very outer layers of the circumbinary envelope. The presence of wind in the system is suggested by the spectrum. The cooler component of the system is definitely a B star of later spectral type than the B1.5V object, with a linewidth that suggests a luminosity certainly not higher than that of a main-sequence star. The ultraviolet continuous spectrum is that of a B1.5V star.